Table 7

Details of each study identified by systematic review which met the inclusion criteria

First author and citationStudy designStudy periodVaccinePopulationNo. cases in exposed to mRNA vaccineDiagnostic criteriaPercentage of cases who were maleAge of casesVaccine doseRisk/Rate Ratio (RR) (95% CI)Incidence (95% CI)
1Barda48Cohort with unvaccinated comparatorDecember 2020 - May 2021ComirnatyIsrael, electronic health recordsMyocarditis n=21; Pericarditis n=27NRNRNRMyocarditis=3.24 (1.55 to 12.44); Pericarditis=1.27 (0.68 to 2.31)NC
2Chouchana25Analysis of VigiBase spontaneous reportsVaccine launch - end June 2021mRNA COVID vaccineVigibase reportsMyocarditis n=1241;
Pericarditis n=851;
Myo-pericarditis n=167;
Pleuro-pericarditis n=18		68.30%Median 33 (21–54) yearsNRNCNC
3Chua49Population cohort study14 June 2021 - 4 September 2021ComirnatyHong Kong adolescents, electronic health recordsn=33 cases (myocarditis/ pericarditis)87.88%Median 15.25 years81.82% followed 2nd doseNCOverall=18.52 (95% CI 11.67 to 29.01);
Males=32.29 (95% CI 22.78 to 45.4);
Females=4.53 (95% CI 1.76 to 11.11)
4Das50Cross sectional study of 25 children aged 12–18 years diagnosed with probable myopericarditis following COVID-19 mRNA vaccination10 May 2021 - 20 June 2021ComirnatyAdolescents presenting at 8 US centresn=25 (myo-pericarditis)88%Range 12–17 years88% followed 2nd doseNCNC
5Diaz51Retrospective cohortVaccine launch - 25 May 2021mrNA COVID vaccine plus AZ vaccine40 US hospitals, electronic health recordsMyocarditis n=20; pericarditis n=35Myocarditis75%; pericarditis 73%Myocarditis cases median 36 (26.3–48.3) years; Pericarditis cases median 59 46–69) yearsNRNCNC
6Eggebrecht52Cohort27 December 2020 - 3 September 2021All COVID vaccines113 patients at cardiology unitComirnaty cases n=85; Spikevax n=1356%Average age 45.9 years, 95% CI 43.2 to 48.757% followed 2nd doseNCNC
7Farahmand26Cohort3 August 2020 – 21 May 2021All COVID vaccinesPatients and employees of the Beth Israel Deaconess Medical Center
(BIDMC), electronic health records		n=750.00%Participants aged 25 years and olderNRAge adjusted rate ratio=9.7 (p=0.04)NC
8Foltran53Analysis of VigiBase spontaneous reports1 January - 14 September 2021mRNA COVID vaccinesVigibase reports for adolescents aged 12–17 yearsn=242 cases (pericarditis and/or myocarditis)85%Mean 15.8 (±1.4 years)1 or 2 dosesNCNC
9Fronza54Retrospective cohortDecember 2019 – November 2021All COVID vaccinesConsecutive adults referred to a tertiary hospital network for MRISpikevax n=12; Comirnaty n=981%Mean (SD) 31 (14) years17 followed 2nd doseNCNC
10Gargano55Analysis of VAERS spontaneous reports29 December 2020 – 11 June 2021mRNA COVID vaccinesVAERS reportsn=122676.2% of 1212 cases where sex availableMedian age 26 years (range 12–94 years)76% followed 2nd dose (where dose was reported)NCNC
11Golino56Observational studyJune - August 2021mRNA COVID vaccinesHospital admissions, University of Insubria, Varese, Italyn=12 (myo-pericarditis)33% of cases were young malesMales aged 29 (±12) yearsNRNCNC
12Hajjo39VAERS analysisVaccine launch – 2 September 2021All COVID vaccinesVAERS reportsMyocarditis=1579;
Pericarditis=1063		myo=77%, peri=65%Range 6–80+years1–3 dosesNCNC
13Hause12VAERS & V-Safe analysis14 December 2020 – 16 July 2021ComirnatyVAERS and V-Safe reports for adolescentsn=379 (myocarditis)NRNRNRNCNC
14Husby57Population-based cohort study1 October 2020 – 5 October 2021All COVID vaccinesDanish health records databases (all individuals in Denmark aged 12 and over)Comirnaty n=48;
Spikevax n=21		NRNRNRNCAbsolute rate within 28 days of vaccination:
Overall=1.7 (95% CI
1.3 to 2.2) per 100 000 vaccinated individuals.
Comirnaty=1.4 (1.0 to 1.8) per 100 000
Spikevax=4.2 (2.6 to 6.4) per 100 000
15 Jain27Retrospective multicentre studyMarch 2021 – June 2021mRNA COVID vaccinesPatients<21 years presenting to 16 US hospitalsComirnaty n=59;
Spikevax n=4		92%Mean 15.6±1.8 years
(range 12–20 years)		62 cases followed 2nd doseNCNC
16Kerneis58Vigibase analysis1967–7 May 2021All COVID vaccinesVigibase reportsComirnaty n=151; Spikevax n=5163.90%Median 35 (IQR 25–50) yearsNRNCNC
17Klein28Vaccine Safety Datalink analysis14 December 2020 – 26 June 2021mRNA COVID vaccinesElectronic health recordsn=87 (myocarditis/ pericarditis)85%Range 12–39 yearsNRNCNC
18Knowlton59Cohort / Case-crossover15 December 2020 – 15 June 2021All COVID vaccinesAdult patients presenting at Intermountain HealthcareComirnaty n=5;
Spikevax n=15		71.40%Median (IQR) 56 (28–70) yearsNRWithin 60 days RR=1.63 (95% CI 0.95 to 2.71);
Within 30 days RR=2.05 (95% CI 1.17 to 3.48)		NC
19Kravchenko60Retrospective cohortNRmRNA COVID-19 vaccinesAll patients referred for cardiac MRI to the Department of Diagnostic and Interventional Radiology, University Hospital BonnComirnaty n=19;
Spikevax n=1		60%Mean age 28±12 years75% followed 2nd doseNCNC
20Lai61Case-control23 February – 2 August 2021Comirnaty and Sinovac CoronaVacPatients aged 12 and over, electronic health records provided by the Hospital Authority (HA) of Hong Kong; linked with population-based vaccination recordsComirnaty n=2062.5% of 160 carditis cases overallMean (SD) age 57.48 (24.23) years overall for vaccinated and unvaccinated participants75.0% followed 2nd doseCarditis aOR=3.57 (95% CI 1.93 to 6.60)NC
21Li49VAERS analysis11 December 2020 – 13 August 2021All COVID vaccinesVAERS reportsComirnaty n=1335 cases;
Spikevax n=703		Spikevax=69.6%, Comirnaty=73.8%Spikevax recipients aged 18 and older, Comirnaty recipients aged 12 and older63.47% followed 2nd doseNCIncidence rate=5.98 (95% CI=5.73 to 6.24) cases per million doses administered
22Li29Cohort10 March – 18 October 2021ComirnatyHong Kong adolescents, electronic health recordsn=43 (myocarditis)88%Mean (SD) 14.86 (1.46) years84% followed 2nd doseNCNC
23Mevorach31Retrospective cohort20 December 2020 – 31 May 2021ComirnatyMedical records, Ministry of Health database (Israel)n=142 (myocarditis)91% of the 95 cases for whom age and sex were available16 years and older91% followed 2nd doseRate Ratio=2.35 (95% CI, 1.10 to 5.02)NC
24Nygaard62Prospective nationwide population-based cohort study15 May 2021 – 15 September 2021mRNA COVID vaccinesHospitalised adolescentsComirnaty n=1587%Range 13–17 years47% after 2nd doseNCMales: 97 per million
Females: 16 per million
25Oh63Retrospective observational study1 June 2021 – 15 October 2021mRNA COVID vaccinesPatients presenting at the Incheon and Daejeon hospitals’ emergency departmentsn=4 (myocarditis)100%Range 17–49 years50% after 2nd doseNCNC
26Oster64VAERS analysisDecember 2020 – August 2021mRNA COVID vaccinesVAERS reportsn=1626 (myocarditis)82%Median=21 years (IQR 16–31)82% after 2nd doseNCNC
27Patone65Population-based cohort studyNRComirnaty or AZEnglandMyocarditis n=397; Pericarditis n=356Myocarditis=50% following 1st dose, 57.8% following 2nd dose; Pericarditis=62.7% following 1st dose, 69.3% following 2nd doseMyocarditis 1st dose mean (SD) 55.2 (22.0) years, myocarditis 2nd dose mean (SD) 61 (22.8) years;
Pericarditis 1st dose mean (SD) 57.6 (20.1) years,
Pericarditis 2nd dose mean (SD) 63.2 (18.7) years		52.1% received 1st dose onlyMyocarditis 1st dose RR=1.31 (95% CI 1.03 to 1.66);
Myocarditis 2nd dose RR=1.30 (95% CI 0.98 to 1.72);
Pericarditis - No association		NC
28Sa66observational study (VAERS)14th Dec 2020 – 30th Sept 2021Comirnaty Spikevax or JanssenUSA population, aged over 18 yearsComirnaty n=1072;
Spikevax n=791		NRn=1573 18–64 years, n=193 65 years and olderNRNCNC
29Simone67retrospective population-based cohort study14 December 2020 – 20 July 2021mRNA COVID vaccinesKaiser Permanente Southern California
(KPSC) members aged 18 years and older		n=15 (myocarditis)100%Median (IQR) 52 (32–59) years86.7% followed 2nd dose1st dose: RR=0.38 (95%CI 0.05 to 1.40)
2nd dose: RR=2.7 (95% CI 1.4 to 4.8)		NC
30Truong68Retrospective cohortUntil 4 July 2021All COVID vaccinesadolescents and young adults<21 years old, presenting at 26 paediatric medical centres across USA and CanadaComirnaty n=131, Spikevax n=590.60%Median 15.8 (range 12.1–20.3) years91.4% followed 2nd doseNCNC
31Tsun Lai69population-based retrospective cohort study1 January 2018 – 30 September 2021Comirnaty or CoronaVacInpatients 12 years and older (Hong Kong)N=38 (myocarditis)NRNR1 or 2 doses1st dose: RR=9.15 (95% CI 1.14 to 73.16);
2nd dose: RR=29.61 (95% CI 4.04 to 217.07)		 
32Witberg70Population-based cohort study42 days after dose 1ComirnatyClalit Health Services, electronic health records for patients aged 16 years or oldern=54 (myocarditis)94%Median (IQR)=27 (21–35) yearsone doseNCOverall: 2.13 (95% CI 1.56 to 2.70) per 100 000
33Yap71Reports to Singapore’s vaccine safety committeeJanuary 2021 – July 2021mRNA COVID vaccinesSingaporen=34 (pericarditis, myocarditis, or concomitant pericarditis and myocarditis)82.40%Myocarditis median 23 (range 12–55) years64% followed second doseNCNC

  • aOR, adjusted OR; NC, not calculated; RR, Risk or Rate Ratio.